The data collection tool for this study is an online survey designed to capture the experiences, health impacts, and sustainability aspirations of children, young people, and parents (CYPP) during and after heatwave events in urban environments. Hosted on platforms like Facebook, Instagram, and Google Forms, the survey features closed and open-ended questions to gather quantitative and qualitative data on health symptoms, daily activities, and coping strategies. It also collects demographic information to understand the diversity of respondents. The tool is designed to be quick and user-friendly, taking about 5 minutes to complete, and is available in multiple languages to ensure inclusivity. Responses are anonymous to protect participants’ privacy.